Polymorphism of human mucin genes in chest disease - Possible significanceof MUC2

Most of the genes that encode epithelial mucins are highly polymorphic due to variations in the length of domains of tandemly repeated (TR) coding seq uence, the part of the apomucin that is heavily glycosylated. We report her e for the first time a difference in the distribution of MUC TR length alle les in chest disease. We examined the distribution of the length alleles of those MUC genes whose expression we have confirmed in the bronchial tree i n an age- and sex-matched series of 50 pairs of atopic patients with and wi thout asthma. There was no significant difference in the distribution of al leles of MUC1, MUC4, MUC5AC, and MUC5B. MUC2, however, showed a highly sign ificant difference in distribution. The atopic, nonasthmatic individuals sh owed an allele distribution that was very different from all our other pati ent and control groups, this group showing a longer mean allele length. The observations suggest that longer MUC2 alleles may help protect atopic indi viduals from developing asthma, though the effect may be due to a linked ge ne. The biological significance of this variation with respect to susceptib ility to asthma will merit further investigation, and it will also be impor tant to substantiate this finding on an independent data set.